The present invention is directed to a new method of treating cognitive deficiencies such as memory loss, Alzheimer's disease, and other dementias using dihydroquinazoline derivatives as the active ingredients.
Tetrahydroacridine derivatives have been reported to possess acetylcholinesterase inhibiting activity, which properties have been found useful in the treatment of cognitive deficit states. For example, tacrine, 9-amino-1,2,3,4-tetrahydroaminoacridine, has proved effective in the alleviation of symptoms of Alzheimer's disease. Dependent on the dosing sequence for effective results, use of tetrahydroaminoacridines may cause liver toxicity. Tetrahydroaminoacridines are also known to be mutagenic.
It has now been found that certain quinazoline derivatives also possess cholinesterase inhibiting activity and are thus useful for treating cognitive deficiencies such as: Alzheimer's disease, senile dementias, multiple infarct dementias, and other conditions where memory and cognitive function improvement or stabilization is desired. The present quinazoline derivatives may also be useful in eliminating symptoms of tardive dyskinesia, e.g., induced by tricyclic antidepressants, Huntington's chorea, and the side effects caused by centrally acting anticholinergics, e.g., tricyclic antidepressants, scopolamine, quinuclidinyl benzilate and the like. The above compounds would also be useful in the treatment of manic depressive disorder.
It is believed that the present quinazoline derivatives lacking the aromatic amine moiety of the tetrahydroaminoacridines will not possess the toxicity of the tetrahydroaminoacridines.